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  • Socket - Adress already in use

    - by Hamza Karmouda
    I'm new to socketand i try to code an Server and client on the same application just to see how it work. here's my code : public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ((Button)this.findViewById(R.id.bouton1)).setOnClickListener(this); } public void onClick(View v) { TCPServer server = new TCPServer(); TCPClient client = new TCPClient(); server.start(); client.start(); } public class TCPServer extends Thread { @Override public void run() { try { ServerSocket s = new ServerSocket(8080,0,InetAddress.getLocalHost()); Socket cli = s.accept(); byte[] b = new byte[512]; int n; InputStream is = cli.getInputStream(); while((n=is.read(b))>0){ Log.d("TCPServer",new String(b)); if(new String(b).contains("\r\n\r\n"))break; b = new byte[512]; } OutputStream os = cli.getOutputStream(); os.write("Hello".getBytes()); } catch (Exception e) { e.printStackTrace(); } } } public class TCPClient extends Thread { @Override public void run() { try { Socket s = new Socket(InetAddress.getLocalHost().getHostAddress(),8080); //Socket s = new Socket("www.google.com",80); //Log.i("",s.getLocalAddress().getHostAddress()); byte[] b = new byte[512]; int n; if (s.isConnected()) { OutputStream os = s.getOutputStream(); os.write("Hi How are you \r\n\r\n".getBytes()); InputStream is = s.getInputStream(); while((n=is.read(b))>0){ Log.d("TCPClient",new String(b)); b = new byte[512]; } } s.close(); } catch (Exception e) { e.printStackTrace(); } } } the code work fine but just for the first time i click my button. the error is java.net.BindException: Address already in use .

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  • how to send image to remote server using web services in android

    - by Aswan
    get image from sdcard and store that image to remote server. i am getting the image from sdcard and i converterd that image to bytearray by using bitmap .but what's the problem if i oberver byte array it is showing some different values it is not matching with .net image byte array conversion. can u pl help if you have any solution it is very urgent to me following is the code i am using can u pl suggest me FileInputStream fin = new FileInputStream(new File("/sdcard/pictures/1.jpg")); BufferedInputStream bis = new BufferedInputStream(fin,3000); byte[] data = new byte[bis.available()]; bis.read(data, 0, data.length); byte[] data1=new byte[data.length]; for (int i = 0; i < data.length; i++) { System.out.print(data[i]); data1[i]=data[i]; } System.out.println("5..................."+data1); Bitmap bitmap = BitmapFactory.decodeByteArray(data1,0,data1.length); System.out.println("6..................."+data1.length); Log.v("hgfjohfjghjdfhgj",""+bitmap); if(bitmap!=null) image.setImageBitmap(bitmap); else Log.e("Bitmap "," Not Created");

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  • Reading and writing in parallel

    - by Malfist
    I want to be able to read and write a large file in parallel, or if not in parallel, at least in blocks so that I don't use up so much memory. This is my current code: // Define memory stream which will be used to hold encrypted data. MemoryStream memoryStream = new MemoryStream(); // Define cryptographic stream (always use Write mode for encryption). CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write); //start encrypting using (BinaryReader reader = new BinaryReader(File.Open(fileIn, FileMode.Open))) { byte[] buffer = new byte[1024 * 1024]; int read = 0; do { read = reader.Read(buffer, 0, buffer.Length); cryptoStream.Write(buffer, 0, read); } while (read == buffer.Length); } // Finish encrypting. cryptoStream.FlushFinalBlock(); // Convert our encrypted data from a memory stream into a byte array. //byte[] cipherTextBytes = memoryStream.ToArray(); //write our memory stream to a file memoryStream.Position = 0; using (BinaryWriter writer = new BinaryWriter(File.Open(fileOut, FileMode.Create))) { byte[] buffer = new byte[1024 * 1024]; int read = 0; do { read = memoryStream.Read(buffer, 0, buffer.Length); writer.Write(buffer, 0, read); } while (read == buffer.Length); } // Close both streams. memoryStream.Close(); cryptoStream.Close(); As you can see, it reads the entire file into memory, encrypts it, then writes it out. If I happen to be encrypting files that are very large (2GB+) it tends not to work, or at the very least, consumes ~97% of my memory. How could I do it in a more effective manner?

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  • How to encrypt a RSAKey using another RSAKey?

    - by Tom Brito
    I know its not the usual thing to do. But the specification I'm implementing is discribed this way, and I cannot run out. I was trying to encrypt the modulus and exponent of the private key, but the following test code raises an exception because the byte array is 1 byte larger then the maximum allowed by RSA block: import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.NoSuchProviderException; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import javax.crypto.Cipher; import org.apache.commons.lang.ArrayUtils; public class TEST { public static KeyPair generateKeyPair() throws NoSuchAlgorithmException, NoSuchProviderException { KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA", "BC"); keyPairGenerator.initialize(1024); return keyPairGenerator.generateKeyPair(); } public static void main(String[] args) throws Exception { KeyPair keyPair = generateKeyPair(); RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); System.out.println("Priv modulus len = " + privateKey.getModulus().bitLength()); System.out.println("Priv exponent len = " + privateKey.getPrivateExponent().bitLength()); System.out.println("Priv modulus toByteArray len = " + privateKey.getModulus().toByteArray().length); byte[] byteArray = privateKey.getModulus().toByteArray(); // the byte at index 0 have no value (in every generation it is always zero) byteArray = ArrayUtils.subarray(byteArray, 1, byteArray.length); System.out.println("byteArray size: " + byteArray.length); RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); Cipher cipher = Cipher.getInstance("RSA", "BC"); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] encryptedBytes = cipher.doFinal(byteArray); System.out.println("Success!"); } } (obs. its just a test, i would never encrypt the private key with its pair public key) The byte array is 128 bytes, the exactly maximum allowed by a RSA block, so why the exception? And how to fix it?

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  • C#. Struct design. Why 16 byte is recommended size?

    - by maxima120
    I read Cwalina book (recommendations on development and design of .NET apps). He says that good designed struct has to be less than 16 bytes in size (for performance purpose). My questions is - why exactly is this? And (more important) can I have larger struct with same efficiency if I run my .NET 3.5 (soon to be .NET 4.0) 64-bit application on i7 under Win7 x64 (is this limitation CPU / OS based)? Just to stress again - I need as efficient struct as it is possible. I try to keep it in stack all the time, the application is heavily multi-threaded and runs on sub-millisecond intervals, the current size of the struct is 64 byte.

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  • How to ensure I get the picture is complete? (in java)

    - by Zenofo
    i using below code to get a picture from URL: URL url=new URL("http://www.google.com/images/logos/ps_logo2.png"); InputStream in=url.openStream(); ByteArrayOutputStream tmpOut = new ByteArrayOutputStream(); byte[] buf = new byte[512]; int len; while (true) { len = in.read(buf); if (len == -1) { break; } tmpOut.write(buf, 0, len); } tmpOut.close(); byte[] picture=tmpOut.toByteArray(); System.out.println(picture.length); this code is okay,but my internet connect is very very bad, so ,I maybe get a broken picture like this: How can I ensure the picture file is complete ? I think you can add this code to try and test this: if (len == -1) { change to if (len == -1 || (int)(Math.random()*100)==1 ) { full test code: URL url=new URL("http://www.google.com/images/logos/ps_logo2.png"); InputStream in=url.openStream(); ByteArrayOutputStream tmpOut = new ByteArrayOutputStream(); byte[] buf = new byte[512]; int len; while (true) { len = in.read(buf); if (len == -1 || (int)(Math.random()*100)==1 ) { break; } tmpOut.write(buf, 0, len); } tmpOut.close(); byte[] picture =tmpOut.toByteArray(); System.out.println(picture.length); thanks for help :)

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  • Few questions on dvd ram/rom

    - by Nrew
    Why other dvd rom/ram can read data from scratched disk and others cannot. For me its a comparison between LG and Lite On. Lite on, gets errors while reading disk with scratches. LG can read disk with scratches with no problems. Why is that? Is it possible to modify the software or the driver of the dvd rom so that it won't get errors when copying data from disk with scratches?

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  • Voice echo in UDP based voice transmission [closed]

    - by Meherzad
    I have coded a java application for voice transmission between to ip in LAN. Here the code. public static Boolean flag= true; public static Boolean recFlag=true; DatagramSocket UDPSocket=null; AudioFormat format = null; TargetDataLine microphone=null; byte[] buffer=null; DatagramPacket UDPPacket=null; public void startChat(String ipAddress){ try{ buffer = new byte[1000]; UDPSocket=new DatagramSocket(1987); Thread th=new Thread(new Listener()); th.start(); microphone = AudioSystem.getTargetDataLine(format); format= new AudioFormat(8000.0f, 16, 1, true, true); UDPPacket = new DatagramPacket(buffer, buffer.length, InetAddress.getByName(ipAddress), 1988); microphone.open(format); microphone.start(); while (flag) { microphone.read(buffer, 0, buffer.length); UDPSocket.send(UDPPacket); } } catch(Exception e){ System.out.println(" ssss "+e.getMessage()); } } public class Listener extends Thread{ byte[] buff=new byte[1000]; DatagramSocket UDPSocket1=null; DatagramPacket recPacket=null; DataLine.Info info = new DataLine.Info(SourceDataLine.class, format); SourceDataLine line=null; @Override public void run(){ try{ UDPSocket1=new DatagramSocket(1988); format= new AudioFormat(8000.0f, 16, 1, true, true); line = (SourceDataLine) AudioSystem.getLine(info); line.open(format); line.start(); } catch(Exception e){ System.out.println("list "+ e.getMessage()); } recPacket=new DatagramPacket(buff, buff.length); while(recFlag){ try{ UDPSocket1.receive(recPacket); buff = (byte[])recPacket.getData(); line.write(buff, 0, buff.length); } catch(Exception e){ System.out.println("errr "+e.getMessage()); } } line.drain(); line.close(); } } Main problem which I am facing that I am getting only echo of my own voice. I am unable to hear voice from the other end only I am hearing is my own voice. Please suggest any solution.

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  • Facebook Game database design

    - by facebook-100000781341887
    Hi, I'm currently develop a facebook mafia like PHP game(of course, a light weight version), here is a simplify database(MySQL) of the game id-a <int3> <for index> uid <chr15> <facebook uid> HP <int3> <health point> exp <int3> <experience> money <int3> <money> list_inventory <chr5> <the inventory user hold...some special here, talk next> ... and 20 other fields just like reputation, num of combat... *the number next to the type is the size(byte) of the type For the list_inventory, there have 40 inventorys in my game, (actually, I have 5 these kind of list in my database), and each user can only contain 1 qty of each inventory, therefore, I assign 5 char for this field and each bit of char as 1 item(5 char * 8 bit = 40 slot), and I will do some manipulation by PHP to extract the data from this 5 byte. OK, I was thinking on this, if this game contains 100,000 user, and only 10% are active, therefore, if use my method, for the space use, 5 byte * 100,000 = 500 KB if I use another method, create a table user_hold_inventory, if the user have the inventory, then insert a record into this table, so, for 10,000 active user, I assume they got all item, but for other, I assume they got no item, here is the fields of the new table id-b <int3> <for index> id-a <int3> <id of the user table> inv_no <int1> <inventory that user hold> for the space use, ([id] (3+3) byte + [inv_no] 1 byte ) * [active user] 10,000 * [all inventory] * 40 = 2.8 MB seems method 2 have use more space, but it consume less CPU power. Please comment these 2 method or please correct me if there have another better method rather than what I think. Another question is, my database contain 26 fields, but I counted 5 of them are not change frquently, should I need to separate it on the other table or not? So many words, thanks for reading :)

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  • XAMPP on windows 7 not working properly

    - by 404Error
    Hey there, I just installed XAMPP lite on Windows 7. I have two drives - C: for the OS and regular files, and an external drive E:. I installed XAMPP lite on E: (on the root), and its been giving me problems. Apache works well enough, but MySQL doesn't work. When I go to http://localhost/phpmyadmin/, it gives me the following error: Error MySQL said: #2003 - Can't connect to MySQL server on 'localhost' (10061) Connection for controluser as defined in your configuration failed. Any ideas as to what could be the problem? I used the zip file for XAMPP lite, the 32 bit version. This is on Windows 7 Home premium. Thanks!

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  • Padding error when using RSA Encryption in C# and Decryption in Java

    - by Matt Shaver
    Currently I am receiving the following error when using Java to decrypt a Base64 encoded RSA encrypted string that was made in C#: javax.crypto.BadPaddingException: Not PKCS#1 block type 2 or Zero padding The setup process between the exchange from .NET and Java is done by creating a private key in the .NET key store then from the PEM file extracted, created use keytool to create a JKS version with the private key. Java loads the already created JKS and decodes the Base64 string into a byte array and then uses the private key to decrypt. Here is the code that I have in C# that creates the encrypted string: public string Encrypt(string value) { byte[] baIn = null; byte[] baRet = null; string keyContainerName = "test"; CspParameters cp = new CspParameters(); cp.Flags = CspProviderFlags.UseMachineKeyStore; cp.KeyContainerName = keyContainerName; RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cp); // Convert the input string to a byte array baIn = UnicodeEncoding.Unicode.GetBytes(value); // Encrypt baRet = rsa.Encrypt(baIn, false); // Convert the encrypted byte array to a base64 string return Convert.ToBase64String(baRet); } Here is the code that I have in Java that decrypts the inputted string: public void decrypt(String base64String) { String keyStorePath = "C:\Key.keystore"; String storepass = "1234"; String keypass = "abcd"; byte[] data = Base64.decode(base64String); byte[] cipherData = null; keystore = KeyStore.getInstance("JKS"); keystore.load(new FileInputStream(keyStorePath), storepass.toCharArray()); RSAPrivateKey privateRSAKey = (RSAPrivateKey) keystore.getKey(alias, keypass.toCharArray()); Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); cipher.init(Cipher.DECRYPT_MODE, privateRSAKey); cipherData = cipher.doFinal(data); System.out.println(new String(cipherData)); } Does anyone see a step missing or where the padding or item needs to be changed? I have done hours of reading on this site and others but haven't really found a concrete solution. You're help is vastly appreciated. Thanks. -Matt

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  • adresse book with C programming, i have problem with library i think, couldn't complite my code

    - by osabri
    I've divided my code in small programm so it can be easy to excute /* ab_error.c : in case of errors following messages will be displayed */ #include "adressbook.h" static char *errormsg[] = { "", "\nNot enough space on disk", "\nCannot open file", "\nCannot read file", "\nCannot write file" }; void check(int error) { switch(error) { case 0: return; case 1: write_file(); case 2: case 3: case 4: system("cls"); fputs(errormsg[error], stderr); exit(error); } } 2nd /* ab_fileio.c : functions for file input/output */ include "adressbook.h" static char ab_file[] = "ADRESSBOOK.DAT"; //file to save the entries int read_file(void) { int error = 0; FILE *fp; ELEMENT *new_e, *last_e = NULL; DATA buffer; if( (fp = fopen(ab_file, "rb")) == NULL) return -1; //no file found while (fread(&buffer, sizeof(DATA), 1, fp) == 1) //reads one list element after another { if( (new_e = make_element()) == NULL) { error = 1; break; //not enough space } new_e->person = buffer; //copy data to new element new_e->next = NULL; if(hol.first == NULL) //list is empty? hol.first = new_e; //yes else last_e->next = new_e; //no last_e = new_e; ++hol.amount; } if( !error && !feof(fp) ) error = 3; //cannot read file fclose(fp); return error; } /-------------------------------/ int write_file(void) { int error = 0; FILE *fp; ELEMENT *p; if( (p = hol.first) == NULL) return 0; //list is empty if( (fp = fopen(ab_file, "wb")) == NULL) return 2; //cannot open while( p!= NULL) { if( fwrite(&p->person, sizeof(DATA), 1, fp) < 1) { error = 4; break; //cannot write } p = p->next; } fclose(fp); return error; } 3rd /* ab_list.c : functions to manipulate the list */ #include "adressbook.h" HOL hol = {0, NULL}; //global definition for head of list /* -------------------- */ ELEMENT *make_element(void) { return (ELEMENT *)malloc( sizeof(ELEMENT) ); } /* -------------------- */ int ins_element( DATA *newdata) { ELEMENT *new_e, *pre_p; if((new_e = make_element()) == NULL) return 1; new_e ->person = *newdata; // copy data to new element pre_p = search(new_e->person.family_name); if(pre_p == NULL) //no person in list { new_e->next = hol.first; //put it to the begin hol.first = new_e; } else { new_e->next = pre_p->next; pre_p->next = new_e; } ++hol.amount; return 0; } int erase_element( char name, char surname ) { return 0; } /* ---------------------*/ ELEMENT *search(char *name) { ELEMENT *sp, *retp; //searchpointer, returnpointer retp = NULL; sp = hol.first; while(sp != NULL && sp->person.family_name != name) { retp = sp; sp = sp->next; } return(retp); } 4th /* ab_screen.c : functions for printing information on screen */ #include "adressbook.h" #include <conio.h> #include <ctype.h> /* standard prompts for in- and output */ static char pgmname[] = "---- Oussama's Adressbook made in splendid C ----"; static char options[] = "\ 1: Enter new adress\n\n\ 2: Delete entry\n\n\ 3: Change entry\n\n\ 4: Print adress\n\n\ Esc: Exit\n\n\n\ Your choice . . .: "; static char prompt[] = "\ Name . . . .:\n\ Surname . . :\n\n\ Street . . .:\n\n\ House number:\n\n\ Postal code :\n\n\ Phone number:"; static char buttons[] = "\ <Esc> = cancel input <Backspace> = correct input\ <Return> = assume"; static char headline[] = "\ Name Surname Street House Postal code Phone number \n\ ------------------------------------------------------------------------"; static char further[] = "\ -------- continue with any key --------"; /* ---------------------------------- */ int menu(void) //show menu and read user input { int c; system ("cls"); set_cur(0,20); puts(pgmname); set_cur(6,0); printf("%s", options); while( (c = getch()) != ESC && (c < '1' || c > '4')) putch('\a'); return c; } /* ---------------------------------- */ int print_adr_book(void) //display adressbook { int line = 1; ELEMENT *p = hol.first; system("cls"); set_cur(0,20); puts(pgmname); set_cur(2,0); puts(headline); set_cur(5,0); while(p != NULL) //run through list and show entries { printf("%5d %-15s ",line, p->person.family_name); printf("%-12s %-15s ", p->person.given_name, p->person.street); printf("%-4d %-5d %-12d\n",p->person.house_number, p->person.postal_code, p->person.phone); p = p->next; if( p == NULL || ++line %16 == 1) //end of list or screen is full { set_cur(24,0); printf("%s",further); if( getch() == ESC) return 0; set_cur(5,0); scroll_up(0,5,24);//puts(headline); } } return 0; } /* -------------------------------------------*/ int make_entry(void) { char cache[50]; DATA newperson; ELEMENT *p; while(1) { system("cls"); set_cur(0,20); puts(pgmname); set_cur(6,0); puts("Please enter new data:"); set_cur(10,0); puts(prompt); set_cur(24,0); printf("%s",buttons); balken(10, 25, MAXL, ' ',0x70); //input name if(input(newperson.family_name, MAXL, ESC, CR) == ESC) return 0; balken(12,25, MAXL, ' ', 0x70); //surname if(input(newperson.given_name, MAXL, ESC, CR) == ESC) return 0; balken(14,25, 30, ' ', 0x70); //street if(input(newperson.street, 30, ESC, CR) == ESC) return 0; balken(16,25, 4, ' ',0x70); //housenumber if(input(cache, 4, ESC, CR) == ESC) return 0; newperson.house_number = atol(cache); //to string balken(18,25, 5, ' ',0x70); //postal code if(input(cache, 5, ESC, CR) == ESC) return 0; newperson.postal_code = atol(cache); //to string balken(20,25, 20, ' ',0x70); //phone number if(input(cache, 20, ESC, CR) == ESC) return 0; newperson.phone = atol(cache); //to string p = search(newperson.phone); if( p!= NULL && p->person.phone == newperson.phone) { set_cur(22,25); puts("phonenumber already exists!"); set_cur(24,0); printf("%s, further"); getch(); continue; } } } 5th /* adress_book_project.c : main program to create an adressbook */ /* copyrights by Oussama Sabri, June 2010 */ #include "adressbook.h" //project header file int main() { int rv, cmd; //return value, user command if ( (rv = read_file() ) == -1) // no data saved yet rv = make_entry(); check(rv); //prompts an error and quits program on disfunction do { switch (cmd = menu())//calls menu and gets user input back { case '1': rv = make_entry(); break; case '2': //delete entry case '3': //changes entry rv = change_entry(cmd); break; case '4': //prints adressbook on screen rv = print_adr_book(); break; case ESC: //end of program system ("cls"); rv = 0; break; } }while(cmd!= ESC); check ( write_file() ); //save adressbook return 0; } 6th /* Getcb.c --> Die Funktion getcb() liefert die naechste * * Tastatureingabe (ruft den BIOS-INT 0x16 auf). * * Return-Wert: * * ASCII-Code bzw. erweiterter Code + 256 */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> int getcb(void) { union REGS intregs; intregs.h.ah = 0; // Subfunktion 0: ein Zeichen // von der Tastatur lesen. int86( 0x16, &intregs, &intregs); if( intregs.h.al != 0) // Falls ASCII-Zeichen, return (intregs.h.al); // dieses zurueckgeben. else // Sonst den erweiterten return (intregs.h.ah + 0x100); // Code + 256 } 7th /* PUTCB.C --> enthaelt die Funktionen * * - putcb() * * - putcb9() * * - balken() * * - input() * * * * Es werden die Funktionen 9 und 14 des Video-Interrupts * * (ROM-BIOS-Interrupt 0x10) verwendet. * * * * Die Prototypen dieser Funktionen stehen in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #define VIDEO_INT 0x10 /*---------------------------------------------------------------- * putcb(c) gibt das Zeichen auf der aktuellen Cursor-Position * am Bildschirm aus. Der Cursor wird versetzt. * Steuerzeichen Back-Space, CR, LF und BELL werden * ausgefuehrt. * Return-Wert: keiner */ void putcb(unsigned char c) /* Gibt das Zeichen in c auf */ { /* den Bildschirm aus. */ union REGS intregs; intregs.h.ah = 14; /* Subfunktion 14 ("Teletype") */ intregs.h.al = c; intregs.h.bl = 0xf; /* Vordergrund-Farbe im */ /* Grafik-Modus. */ int86(VIDEO_INT, &intregs, &intregs); } /*---------------------------------------------------------------- * putcb9(c,count,mode) gibt das Zeichen in c count-mal im * angegebenen Modus auf der aktuellen * Cursor-Position am Bildschirm aus. * Der Cursor wird nicht versetzt. * * Return-Wert: keiner */ void putcb9( unsigned char c, /* das Zeichen */ unsigned count, /* die Anzahl */ unsigned mode ) /* Low-Byte: das Atrribut */ { /* High-Byte: die Bildschirmseite*/ union REGS intregs; intregs.h.ah = 9; /* Subfunktion 9 des Int 0x10 */ intregs.h.al = c; intregs.x.bx = mode; intregs.x.cx = count; int86( VIDEO_INT, &intregs, &intregs); } /*---------------------------------------------------------------- * balken() positioniert den Cursor und zeichnet einen Balken, * wobei Position, L„nge, Fllzeichen und Attribut * als Argumente bergeben werden. * Der Cursor bleibt auf der ersten Position im Balken. */ void balken( unsigned int zeile, /* Start-Position */ unsigned int spalte, unsigned int laenge, /* Laenge des Balkens */ unsigned char c, /* Fuellzeichen */ unsigned int modus) /* Low-Byte: Attribut */ /* High-Byte: Bildschirmseite */ { union REGS intregs; intregs.h.ah = 2; /* Cursor auf der angegebenen */ intregs.h.dh = zeile; /* Bildschirmseite versetzen. */ intregs.h.dl = spalte; intregs.h.bh = (modus >> 8); int86(VIDEO_INT, &intregs, &intregs); putcb9(c, laenge, modus); /* Balken ausgeben. */ } /*---------------------------------------------------------------- * input() liest Zeichen von der Tastatur ein und haengt '\0' an. * Mit Backspace kann die Eingabe geloescht werden. * Das Attribut am Bildschirm bleibt erhalten. * * Argumente: 1. Zeiger auf den Eingabepuffer. * 2. Anzahl maximal einzulesender Zeichen. * 3. Die optionalen Argumente: Zeichen, mit denen die * Eingabe abgebrochen werden kann. * Diese Liste muá mit CR = '\r' enden! * Return-Wert: Das Zeichen, mit dem die Eingabe abgebrochen wurde. */ #include <stdarg.h> int getcb( void); /* Zum Lesen der Tastatur */ int input(char *puffer, int max,... ) { int c; /* aktuelles Zeichen */ int breakc; /* Abruchzeichen */ int nc = 0; /* Anzahl eingelesener Zeichen */ va_list argp; /* Zeiger auf die weiteren Arumente */ while(1) { *puffer = '\0'; va_start(argp, max); /* argp initialisieren */ c = getcb(); do /* Mit Zeichen der Abbruchliste vergleichen */ if(c == (breakc = va_arg(argp,int)) ) return(breakc); while( breakc != '\r' ); va_end( argp); if( c == '\b' && nc > 0) /* Backspace? */ { --nc; --puffer; putcb(c); putcb(' '); putcb(c); } else if( c >= 32 && c <= 255 && nc < max ) { ++nc; *puffer++ = c; putcb(c); } else if( nc == max) putcb('\7'); /* Ton ausgeben */ } } 8th /* Video.c --> Enthaelt die Funktionen * cls(), * scroll_up(), scroll_down(), * set_cur(), get_cur(), * set_screen_page(), get_screen_page() * * Die Prototypen dieser Funktionen befinden sich in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #include "bio.h" #define VIDEO_INT 0x10 typedef unsigned char BYTE; void scroll_up( int anzahl, int anf_zeile, int end_zeile) { /* Fenster hoch rollen. */ union REGS intregs; intregs.x.ax = 0x600 + anzahl; /* Subfunktion AH = 6, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void scroll_down( int anzahl, int anf_zeile, int end_zeile) { /* Fenster runter rollen. */ union REGS intregs; intregs.x.ax = 0x700 + anzahl; /* Subfunktion AH = 7, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void set_cur( int zeile, int spalte) /* versetzt den Cursor */ { /* der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 2; intregs.h.dh = (BYTE)zeile; intregs.h.dl = (BYTE)spalte; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); } void get_cur(int *zeile, int *spalte) /* holt die Cursor- */ { /* Position der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 3; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); *zeile = (unsigned)intregs.h.dh; *spalte = (unsigned)intregs.h.dl; } void cls(void) { scroll_up(0,0,24); /* Gesamten Bildschirm loeschen. */ set_cur(0,0); /* Cursor in Home-Position. */ } int get_screen_page(void) /* Aktuelle Bildschirmseite holen.*/ { union REGS intregs; intregs.h.ah = 15; /* Subfunktion AH = 15: */ /* Bildschirm-Modus feststellen. */ int86(VIDEO_INT, &intregs, &intregs); return (intregs.h.bh); } void set_screen_page(int seite) /* setzt die aktive Seite des */ { /* Bildschirmpuffers auf die */ /* angegebene Seite. */ union REGS intregs; intregs.x.ax = 0x500 + seite; /* Subfunktion AH = 5 */ int86(VIDEO_INT, &intregs, &intregs); } /* ------------------------------------------------------------- Ein kleines Testprogramm : */ /* #include <stdio.h> int main() { cls(); set_cur(23, 0); printf("Weiter mit <Return>\n"); set_cur(12, 20); printf("Ein Test!\n"); getchar(); scroll_up(3, 5, 20); getchar(); scroll_down(6, 5, 20); getchar(); set_screen_page(1); printf("\nAuf der 2. Seite !\n"); getchar(); set_screen_page(0); set_cur(0,0); printf("\nWieder auf der 1. Seite !\n"); getchar(); cls(); return 0; } */ /* Video.c --> Enthaelt die Funktionen * cls(), * scroll_up(), scroll_down(), * set_cur(), get_cur(), * set_screen_page(), get_screen_page() * * Die Prototypen dieser Funktionen befinden sich in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #include "bio.h" #define VIDEO_INT 0x10 typedef unsigned char BYTE; void scroll_up( int anzahl, int anf_zeile, int end_zeile) { /* Fenster hoch rollen. */ union REGS intregs; intregs.x.ax = 0x600 + anzahl; /* Subfunktion AH = 6, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void scroll_down( int anzahl, int anf_zeile, int end_zeile) { /* Fenster runter rollen. */ union REGS intregs; intregs.x.ax = 0x700 + anzahl; /* Subfunktion AH = 7, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void set_cur( int zeile, int spalte) /* versetzt den Cursor */ { /* der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 2; intregs.h.dh = (BYTE)zeile; intregs.h.dl = (BYTE)spalte; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); } void get_cur(int *zeile, int *spalte) /* holt die Cursor- */ { /* Position der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 3; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); *zeile = (unsigned)intregs.h.dh; *spalte = (unsigned)intregs.h.dl; } void cls(void) { scroll_up(0,0,24); /* Gesamten Bildschirm loeschen. */ set_cur(0,0); /* Cursor in Home-Position. */ } int get_screen_page(void) /* Aktuelle Bildschirmseite holen.*/ { union REGS intregs; intregs.h.ah = 15; /* Subfunktion AH = 15: */ /* Bildschirm-Modus feststellen. */ int86(VIDEO_INT, &intregs, &intregs); return (intregs.h.bh); } void set_screen_page(int seite) /* setzt die aktive Seite des */ { /* Bildschirmpuffers auf die */ /* angegebene Seite. */ union REGS intregs; intregs.x.ax = 0x500 + seite; /* Subfunktion AH = 5 */ int86(VIDEO_INT, &intregs, &intregs); } /* ------------------------------------------------------------- Ein kleines Testprogramm : */ /* #include <stdio.h> int main() { cls(); set_cur(23, 0); printf("Weiter mit <Return>\n"); set_cur(12, 20); printf("Ein Test!\n"); getchar(); scroll_up(3, 5, 20); getchar(); scroll_down(6, 5, 20); getchar(); set_screen_page(1); printf("\nAuf der 2. Seite !\n"); getchar(); set_screen_page(0); set_cur(0,0); printf("\nWieder auf der 1. Seite !\n"); getchar(); cls(); return 0; } */ /* BIO.H --> Enthaelt die Prototypen der BIOS-Funktionen. */ /* --- Funktionen in VIDEO.C --- */ extern void scroll_up(int anzahl, int anf_zeile,int end_zeile); extern void scroll_down(int anzahl, int anf_zeile, int end_zeile); extern void set_cur(int zeile, int spalte); extern void get_cur(int *zeile, int *spalte); extern void cls(void); extern int get_screen_page(void); extern void set_screen_page(int page); /* --- Funktionen in GETCB.C / PUTCB.C --- */ extern int getcb(void); extern void putcb(int c); extern void putcb9(int c, unsigned count, unsigned modus); extern void balken(int zeile, int spalte, int laenge, int c, unsigned modus); extern int input(char *puffer, int max,... ); need your help, can't find my mistakes:((

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  • C# SerialPort - Problems mixing ports with different baud rates.

    - by GrandAdmiral
    Greetings, I have two devices that I would like to connect over a serial interface, but they have incompatible connections. To get around this problem, I connected them both to my PC and I'm working on a C# program that will route traffic on COM port X to COM port Y and vice versa. The program connects to two COM ports. In the data received event handler, I read in incoming data and write it to the other COM port. To do this, I have the following code: private void HandleDataReceived(SerialPort inPort, SerialPort outPort) { byte[] data = new byte[1]; while (inPort.BytesToRead > 0) { // Read the data data[0] = (byte)inPort.ReadByte(); // Write the data if (outPort.IsOpen) { outPort.Write(data, 0, 1); } } } That code worked fine as long as the outgoing COM port operated at a higher baud rate than the incoming COM port. If the incoming COM port was faster than the outgoing COM port, I started missing data. I had to correct the code like this: private void HandleDataReceived(SerialPort inPort, SerialPort outPort) { byte[] data = new byte[1]; while (inPort.BytesToRead > 0) { // Read the data data[0] = (byte)inPort.ReadByte(); // Write the data if (outPort.IsOpen) { outPort.Write(data, 0, 1); while (outPort.BytesToWrite > 0); //<-- Change to fix problem } } } I don't understand why I need that fix. I'm new to C# (this is my first program), so I'm wondering if there is something I am missing. The SerialPort defaults to a 2048 byte write buffer and my commands are less than ten bytes. The write buffer should have the ability to buffer the data until it can be written to a slower COM port. In summary, I'm receiving data on COM X and writing the data to COM Y. COM X is connected at a faster baud rate than COM Y. Why doesn't the buffering in the write buffer handle this difference? Why does it seem that I need to wait for the write buffer to drain to avoid losing data? Thanks!

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  • Need help receiving ByteArray data

    - by k80sg
    Hi folks, I am trying to receive byte array data from a machine. It sends out 3 different types of data structure each with different number of fields which consist of mostly int and a few floats, and byte sizes, the first being 320 bytes, 420 for the second type and 560 for the third. When the sending program is launched, it fires all 3 types of data simultaneouly with an interval of 1 sec. Example: Sending order: Pack1 - 320 bytes 1 sec later Pack2 - 420 bytes 1 sec later Pack3 - 560 bytes 1 sec later Pack1 - 320 bytes ... .. . How do I check the incoming byte size before passing it to: byte[] handsize = new byte[bytesize]; as the data I receive are all out of order, for instance using the following the read all int: System.out.println("Reading data in int format:" + " " + datainput.readInt()); I get many different sets of values whenever I run my prog although with some valid field data but they are all over the place. I am not too sure how exactly should I do it but I tried the following and apparently my data fields are not receiving in correct sequence: BufferedInputStream bais = new BufferedInputStream(requestSocket.getInputStream()); DataInputStream datainput = new DataInputStream(bais); byte[] handsize = new byte[560]; datainput.readFully(handsize); int n = 0; int intByte[] = new int[140]; for (int i = 0; i < 140 ; i++) { System.out.println("Reading data in int format:" + " " + datainput.readInt()); intByte[n] = datainput.readInt(); n = n + 1; System.out.println("The value in array is:" + intByte[0]); System.out.println("The value in array is:" + intByte[1]); System.out.println("The value in array is:" + intByte[2]); System.out.println("The value in array is:" + intByte[3]); Also from the above code, the order of the values printed out with System.out.println("Reading data in int format:" + " " + datainput.readInt()); and System.out.println("The value in array is:" + intByte[0]); System.out.println("The value in array is:" + intByte[1]); are different. Any help will be appreciated. Thanks

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  • Address book with C programming; cannot compile my code.

    - by osabri
    I've divided my code into small programs so it can be easy to excute /* ab_error.c : in case of errors following messages will be displayed */ #include "adressbook.h" static char *errormsg[] = { "", "\nNot enough space on disk", "\nCannot open file", "\nCannot read file", "\nCannot write file" }; void check(int error) { switch(error) { case 0: return; case 1: write_file(); case 2: case 3: case 4: system("cls"); fputs(errormsg[error], stderr); exit(error); } } 2nd /* ab_fileio.c : functions for file input/output */ #include "adressbook.h" static char ab_file[] = "ADRESSBOOK.DAT"; //file to save the entries int read_file(void) { int error = 0; FILE *fp; ELEMENT *new_e, *last_e = NULL; DATA buffer; if( (fp = fopen(ab_file, "rb")) == NULL) return -1; //no file found while (fread(&buffer, sizeof(DATA), 1, fp) == 1) //reads one list element after another { if( (new_e = make_element()) == NULL) { error = 1; break; //not enough space } new_e->person = buffer; //copy data to new element new_e->next = NULL; if(hol.first == NULL) //list is empty? hol.first = new_e; //yes else last_e->next = new_e; //no last_e = new_e; ++hol.amount; } if( !error && !feof(fp) ) error = 3; //cannot read file fclose(fp); return error; } /*-------------------------------*/ int write_file(void) { int error = 0; FILE *fp; ELEMENT *p; if( (p = hol.first) == NULL) return 0; //list is empty if( (fp = fopen(ab_file, "wb")) == NULL) return 2; //cannot open while( p!= NULL) { if( fwrite(&p->person, sizeof(DATA), 1, fp) < 1) { error = 4; break; //cannot write } p = p->next; } fclose(fp); return error; } 3rd /* ab_list.c : functions to manipulate the list */ #include "adressbook.h" HOL hol = {0, NULL}; //global definition for head of list /* -------------------- */ ELEMENT *make_element(void) { return (ELEMENT *)malloc( sizeof(ELEMENT) ); } /* -------------------- */ int ins_element( DATA *newdata) { ELEMENT *new_e, *pre_p; if((new_e = make_element()) == NULL) return 1; new_e ->person = *newdata; // copy data to new element pre_p = search(new_e->person.family_name); if(pre_p == NULL) //no person in list { new_e->next = hol.first; //put it to the begin hol.first = new_e; } else { new_e->next = pre_p->next; pre_p->next = new_e; } ++hol.amount; return 0; } int erase_element( char name, char surname ) { return 0; } /* ---------------------*/ ELEMENT *search(char *name) { ELEMENT *sp, *retp; //searchpointer, returnpointer retp = NULL; sp = hol.first; while(sp != NULL && sp->person.family_name != name) { retp = sp; sp = sp->next; } return(retp); } 4th /* ab_screen.c : functions for printing information on screen */ #include "adressbook.h" #include <conio.h> #include <ctype.h> /* standard prompts for in- and output */ static char pgmname[] = "---- Oussama's Adressbook made in splendid C ----"; static char options[] = "\ 1: Enter new adress\n\n\ 2: Delete entry\n\n\ 3: Change entry\n\n\ 4: Print adress\n\n\ Esc: Exit\n\n\n\ Your choice . . .: "; static char prompt[] = "\ Name . . . .:\n\ Surname . . :\n\n\ Street . . .:\n\n\ House number:\n\n\ Postal code :\n\n\ Phone number:"; static char buttons[] = "\ <Esc> = cancel input <Backspace> = correct input\ <Return> = assume"; static char headline[] = "\ Name Surname Street House Postal code Phone number \n\ ------------------------------------------------------------------------"; static char further[] = "\ -------- continue with any key --------"; /* ---------------------------------- */ int menu(void) //show menu and read user input { int c; system ("cls"); set_cur(0,20); puts(pgmname); set_cur(6,0); printf("%s", options); while( (c = getch()) != ESC && (c < '1' || c > '4')) putch('\a'); return c; } /* ---------------------------------- */ int print_adr_book(void) //display adressbook { int line = 1; ELEMENT *p = hol.first; system("cls"); set_cur(0,20); puts(pgmname); set_cur(2,0); puts(headline); set_cur(5,0); while(p != NULL) //run through list and show entries { printf("%5d %-15s ",line, p->person.family_name); printf("%-12s %-15s ", p->person.given_name, p->person.street); printf("%-4d %-5d %-12d\n",p->person.house_number, p->person.postal_code, p->person.phone); p = p->next; if( p == NULL || ++line %16 == 1) //end of list or screen is full { set_cur(24,0); printf("%s",further); if( getch() == ESC) return 0; set_cur(5,0); scroll_up(0,5,24);//puts(headline); } } return 0; } /* -------------------------------------------*/ int make_entry(void) { char cache[50]; DATA newperson; ELEMENT *p; while(1) { system("cls"); set_cur(0,20); puts(pgmname); set_cur(6,0); puts("Please enter new data:"); set_cur(10,0); puts(prompt); set_cur(24,0); printf("%s",buttons); balken(10, 25, MAXL, ' ',0x70); //input name if(input(newperson.family_name, MAXL, ESC, CR) == ESC) return 0; balken(12,25, MAXL, ' ', 0x70); //surname if(input(newperson.given_name, MAXL, ESC, CR) == ESC) return 0; balken(14,25, 30, ' ', 0x70); //street if(input(newperson.street, 30, ESC, CR) == ESC) return 0; balken(16,25, 4, ' ',0x70); //housenumber if(input(cache, 4, ESC, CR) == ESC) return 0; newperson.house_number = atol(cache); //to string balken(18,25, 5, ' ',0x70); //postal code if(input(cache, 5, ESC, CR) == ESC) return 0; newperson.postal_code = atol(cache); //to string balken(20,25, 20, ' ',0x70); //phone number if(input(cache, 20, ESC, CR) == ESC) return 0; newperson.phone = atol(cache); //to string p = search(newperson.phone); if( p!= NULL && p->person.phone == newperson.phone) { set_cur(22,25); puts("phonenumber already exists!"); set_cur(24,0); printf("%s, further"); getch(); continue; } } } 5th /* adress_book_project.c : main program to create an adressbook */ /* copyrights by Oussama Sabri, June 2010 */ #include "adressbook.h" //project header file int main() { int rv, cmd; //return value, user command if ( (rv = read_file() ) == -1) // no data saved yet rv = make_entry(); check(rv); //prompts an error and quits program on disfunction do { switch (cmd = menu())//calls menu and gets user input back { case '1': rv = make_entry(); break; case '2': //delete entry case '3': //changes entry rv = change_entry(cmd); break; case '4': //prints adressbook on screen rv = print_adr_book(); break; case ESC: //end of program system ("cls"); rv = 0; break; } }while(cmd!= ESC); check ( write_file() ); //save adressbook return 0; } 6th /* Getcb.c --> Die Funktion getcb() liefert die naechste * * Tastatureingabe (ruft den BIOS-INT 0x16 auf). * * Return-Wert: * * ASCII-Code bzw. erweiterter Code + 256 */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> int getcb(void) { union REGS intregs; intregs.h.ah = 0; // Subfunktion 0: ein Zeichen // von der Tastatur lesen. int86( 0x16, &intregs, &intregs); if( intregs.h.al != 0) // Falls ASCII-Zeichen, return (intregs.h.al); // dieses zurueckgeben. else // Sonst den erweiterten return (intregs.h.ah + 0x100); // Code + 256 } 7th /* PUTCB.C --> enthaelt die Funktionen * * - putcb() * * - putcb9() * * - balken() * * - input() * * * * Es werden die Funktionen 9 und 14 des Video-Interrupts * * (ROM-BIOS-Interrupt 0x10) verwendet. * * * * Die Prototypen dieser Funktionen stehen in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #define VIDEO_INT 0x10 /*---------------------------------------------------------------- * putcb(c) gibt das Zeichen auf der aktuellen Cursor-Position * am Bildschirm aus. Der Cursor wird versetzt. * Steuerzeichen Back-Space, CR, LF und BELL werden * ausgefuehrt. * Return-Wert: keiner */ void putcb(unsigned char c) /* Gibt das Zeichen in c auf */ { /* den Bildschirm aus. */ union REGS intregs; intregs.h.ah = 14; /* Subfunktion 14 ("Teletype") */ intregs.h.al = c; intregs.h.bl = 0xf; /* Vordergrund-Farbe im */ /* Grafik-Modus. */ int86(VIDEO_INT, &intregs, &intregs); } /*---------------------------------------------------------------- * putcb9(c,count,mode) gibt das Zeichen in c count-mal im * angegebenen Modus auf der aktuellen * Cursor-Position am Bildschirm aus. * Der Cursor wird nicht versetzt. * * Return-Wert: keiner */ void putcb9( unsigned char c, /* das Zeichen */ unsigned count, /* die Anzahl */ unsigned mode ) /* Low-Byte: das Atrribut */ { /* High-Byte: die Bildschirmseite*/ union REGS intregs; intregs.h.ah = 9; /* Subfunktion 9 des Int 0x10 */ intregs.h.al = c; intregs.x.bx = mode; intregs.x.cx = count; int86( VIDEO_INT, &intregs, &intregs); } /*---------------------------------------------------------------- * balken() positioniert den Cursor und zeichnet einen Balken, * wobei Position, L„nge, Fllzeichen und Attribut * als Argumente bergeben werden. * Der Cursor bleibt auf der ersten Position im Balken. */ void balken( unsigned int zeile, /* Start-Position */ unsigned int spalte, unsigned int laenge, /* Laenge des Balkens */ unsigned char c, /* Fuellzeichen */ unsigned int modus) /* Low-Byte: Attribut */ /* High-Byte: Bildschirmseite */ { union REGS intregs; intregs.h.ah = 2; /* Cursor auf der angegebenen */ intregs.h.dh = zeile; /* Bildschirmseite versetzen. */ intregs.h.dl = spalte; intregs.h.bh = (modus >> 8); int86(VIDEO_INT, &intregs, &intregs); putcb9(c, laenge, modus); /* Balken ausgeben. */ } /*---------------------------------------------------------------- * input() liest Zeichen von der Tastatur ein und haengt '\0' an. * Mit Backspace kann die Eingabe geloescht werden. * Das Attribut am Bildschirm bleibt erhalten. * * Argumente: 1. Zeiger auf den Eingabepuffer. * 2. Anzahl maximal einzulesender Zeichen. * 3. Die optionalen Argumente: Zeichen, mit denen die * Eingabe abgebrochen werden kann. * Diese Liste muá mit CR = '\r' enden! * Return-Wert: Das Zeichen, mit dem die Eingabe abgebrochen wurde. */ #include <stdarg.h> int getcb( void); /* Zum Lesen der Tastatur */ int input(char *puffer, int max,... ) { int c; /* aktuelles Zeichen */ int breakc; /* Abruchzeichen */ int nc = 0; /* Anzahl eingelesener Zeichen */ va_list argp; /* Zeiger auf die weiteren Arumente */ while(1) { *puffer = '\0'; va_start(argp, max); /* argp initialisieren */ c = getcb(); do /* Mit Zeichen der Abbruchliste vergleichen */ if(c == (breakc = va_arg(argp,int)) ) return(breakc); while( breakc != '\r' ); va_end( argp); if( c == '\b' && nc > 0) /* Backspace? */ { --nc; --puffer; putcb(c); putcb(' '); putcb(c); } else if( c >= 32 && c <= 255 && nc < max ) { ++nc; *puffer++ = c; putcb(c); } else if( nc == max) putcb('\7'); /* Ton ausgeben */ } } 8th /* Video.c --> Enthaelt die Funktionen * cls(), * scroll_up(), scroll_down(), * set_cur(), get_cur(), * set_screen_page(), get_screen_page() * * Die Prototypen dieser Funktionen befinden sich in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #include "bio.h" #define VIDEO_INT 0x10 typedef unsigned char BYTE; void scroll_up( int anzahl, int anf_zeile, int end_zeile) { /* Fenster hoch rollen. */ union REGS intregs; intregs.x.ax = 0x600 + anzahl; /* Subfunktion AH = 6, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void scroll_down( int anzahl, int anf_zeile, int end_zeile) { /* Fenster runter rollen. */ union REGS intregs; intregs.x.ax = 0x700 + anzahl; /* Subfunktion AH = 7, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void set_cur( int zeile, int spalte) /* versetzt den Cursor */ { /* der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 2; intregs.h.dh = (BYTE)zeile; intregs.h.dl = (BYTE)spalte; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); } void get_cur(int *zeile, int *spalte) /* holt die Cursor- */ { /* Position der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 3; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); *zeile = (unsigned)intregs.h.dh; *spalte = (unsigned)intregs.h.dl; } void cls(void) { scroll_up(0,0,24); /* Gesamten Bildschirm loeschen. */ set_cur(0,0); /* Cursor in Home-Position. */ } int get_screen_page(void) /* Aktuelle Bildschirmseite holen.*/ { union REGS intregs; intregs.h.ah = 15; /* Subfunktion AH = 15: */ /* Bildschirm-Modus feststellen. */ int86(VIDEO_INT, &intregs, &intregs); return (intregs.h.bh); } void set_screen_page(int seite) /* setzt die aktive Seite des */ { /* Bildschirmpuffers auf die */ /* angegebene Seite. */ union REGS intregs; intregs.x.ax = 0x500 + seite; /* Subfunktion AH = 5 */ int86(VIDEO_INT, &intregs, &intregs); } /* ------------------------------------------------------------- Ein kleines Testprogramm : */ /* #include <stdio.h> int main() { cls(); set_cur(23, 0); printf("Weiter mit <Return>\n"); set_cur(12, 20); printf("Ein Test!\n"); getchar(); scroll_up(3, 5, 20); getchar(); scroll_down(6, 5, 20); getchar(); set_screen_page(1); printf("\nAuf der 2. Seite !\n"); getchar(); set_screen_page(0); set_cur(0,0); printf("\nWieder auf der 1. Seite !\n"); getchar(); cls(); return 0; } */ /* Video.c --> Enthaelt die Funktionen * cls(), * scroll_up(), scroll_down(), * set_cur(), get_cur(), * set_screen_page(), get_screen_page() * * Die Prototypen dieser Funktionen befinden sich in BIO.H */ /* Hinweis: Es muss ein DOS-Compiler verwendet werden. * * (z.B. der GNU-Compiler fuer DOS auf der CD) */ #include <dos.h> #include "bio.h" #define VIDEO_INT 0x10 typedef unsigned char BYTE; void scroll_up( int anzahl, int anf_zeile, int end_zeile) { /* Fenster hoch rollen. */ union REGS intregs; intregs.x.ax = 0x600 + anzahl; /* Subfunktion AH = 6, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void scroll_down( int anzahl, int anf_zeile, int end_zeile) { /* Fenster runter rollen. */ union REGS intregs; intregs.x.ax = 0x700 + anzahl; /* Subfunktion AH = 7, */ /* AL = Anzahl Zeilen. */ intregs.x.cx = anf_zeile << 8; /* CH=anf_zeile, cl=0 */ intregs.x.dx = (end_zeile <<8) | 79; /* DH=end_zeile,DL=79 */ intregs.h.bh = 7; /* normales Attribut */ int86(VIDEO_INT, &intregs, &intregs); } void set_cur( int zeile, int spalte) /* versetzt den Cursor */ { /* der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 2; intregs.h.dh = (BYTE)zeile; intregs.h.dl = (BYTE)spalte; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); } void get_cur(int *zeile, int *spalte) /* holt die Cursor- */ { /* Position der aktuellen Bildschirmseite.*/ union REGS intregs; intregs.h.ah = 3; intregs.h.bh = (BYTE)get_screen_page(); int86(VIDEO_INT, &intregs, &intregs); *zeile = (unsigned)intregs.h.dh; *spalte = (unsigned)intregs.h.dl; } void cls(void) { scroll_up(0,0,24); /* Gesamten Bildschirm loeschen. */ set_cur(0,0); /* Cursor in Home-Position. */ } int get_screen_page(void) /* Aktuelle Bildschirmseite holen.*/ { union REGS intregs; intregs.h.ah = 15; /* Subfunktion AH = 15: */ /* Bildschirm-Modus feststellen. */ int86(VIDEO_INT, &intregs, &intregs); return (intregs.h.bh); } void set_screen_page(int seite) /* setzt die aktive Seite des */ { /* Bildschirmpuffers auf die */ /* angegebene Seite. */ union REGS intregs; intregs.x.ax = 0x500 + seite; /* Subfunktion AH = 5 */ int86(VIDEO_INT, &intregs, &intregs); } /* ------------------------------------------------------------- Ein kleines Testprogramm : */ /* #include <stdio.h> int main() { cls(); set_cur(23, 0); printf("Weiter mit <Return>\n"); set_cur(12, 20); printf("Ein Test!\n"); getchar(); scroll_up(3, 5, 20); getchar(); scroll_down(6, 5, 20); getchar(); set_screen_page(1); printf("\nAuf der 2. Seite !\n"); getchar(); set_screen_page(0); set_cur(0,0); printf("\nWieder auf der 1. Seite !\n"); getchar(); cls(); return 0; } */ /* BIO.H --> Enthaelt die Prototypen der BIOS-Funktionen. */ /* --- Funktionen in VIDEO.C --- */ extern void scroll_up(int anzahl, int anf_zeile,int end_zeile); extern void scroll_down(int anzahl, int anf_zeile, int end_zeile); extern void set_cur(int zeile, int spalte); extern void get_cur(int *zeile, int *spalte); extern void cls(void); extern int get_screen_page(void); extern void set_screen_page(int page); /* --- Funktionen in GETCB.C / PUTCB.C --- */ extern int getcb(void); extern void putcb(int c); extern void putcb9(int c, unsigned count, unsigned modus); extern void balken(int zeile, int spalte, int laenge, int c, unsigned modus); extern int input(char *puffer, int max,... ); need your help, can't find my mistakes:((

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  • Marshal.PtrToStructure (and back again) and generic solution for endianness swapping

    - by cgyDeveloper
    I have a system where a remote agent sends serialized structures (from and embedded C system) for me to read and store via IP/UDP. In some cases I need to send back the same structure types. I thought I had a nice setup using Marshal.PtrToStructure (receive) and Marshal.StructureToPtr (send). However, a small gotcha is that the network big endian integers need to be converted to my x86 little endian format to be used locally. When I'm sending them off again, big endian is the way to go. Here are the functions in question: private static T BytesToStruct<T>(ref byte[] rawData) where T: struct { T result = default(T); GCHandle handle = GCHandle.Alloc(rawData, GCHandleType.Pinned); try { IntPtr rawDataPtr = handle.AddrOfPinnedObject(); result = (T)Marshal.PtrToStructure(rawDataPtr, typeof(T)); } finally { handle.Free(); } return result; } private static byte[] StructToBytes<T>(T data) where T: struct { byte[] rawData = new byte[Marshal.SizeOf(data)]; GCHandle handle = GCHandle.Alloc(rawData, GCHandleType.Pinned); try { IntPtr rawDataPtr = handle.AddrOfPinnedObject(); Marshal.StructureToPtr(data, rawDataPtr, false); } finally { handle.Free(); } return rawData; } And a quick example structure that might be used like this: byte[] data = this.sock.Receive(ref this.ipep); Request request = BytesToStruct<Request>(ref data); Where the structure in question looks like: [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)] private struct Request { public byte type; public short sequence; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)] public byte[] address; } What (generic) way can I swap the endianness when marshalling the structures? My need is such that the locally stored 'public short sequence' in this example will be little-endian for displaying to the user. I don't want to have to swap the endianness on a structure-specific way. My first thought was to use Reflection, but I'm not very familiar with that feature. Also, I hoped that there would be a better solution out there that somebody could point me towards. Thanks in advance :)

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  • hashing password giving different results

    - by geoff
    I am taking over a system that a previous developer wrote. The system has an administrator approve a user account and when they do that the system uses the following method to hash a password and save it to the database. It sends the unhashed password to the user. When the user logs in the system uses the exact same method to hash what the user enters and compares it to the database value. We've run into a couple of times when the database entry doesn't match the user's entry whey they should. So it appears that the method isn't always hashing the value the same. Does anyone know if this method of hashing isn't reliable and how to make it reliable? Thanks. private string HashPassword(string password) { string hashedPassword = string.Empty; // Convert plain text into a byte array. byte[] plainTextBytes = Encoding.UTF8.GetBytes(password); // Allocate array, which will hold plain text and salt. byte[] plainTextWithSaltBytes = new byte[plainTextBytes.Length + SALT.Length]; // Copy plain text bytes into resulting array. for(int i = 0; i < plainTextBytes.Length; i++) plainTextWithSaltBytes[i] = plainTextBytes[i]; // Append salt bytes to the resulting array. for(int i = 0; i < SALT.Length; i++) plainTextWithSaltBytes[plainTextBytes.Length + i] = SALT[i]; // Because we support multiple hashing algorithms, we must define // hash object as a common (abstract) base class. We will specify the // actual hashing algorithm class later during object creation. HashAlgorithm hash = new SHA256Managed(); // Compute hash value of our plain text with appended salt. byte[] hashBytes = hash.ComputeHash(plainTextWithSaltBytes); // Create array which will hold hash and original salt bytes. byte[] hashWithSaltBytes = new byte[hashBytes.Length + SALT.Length]; // Copy hash bytes into resulting array. for(int i = 0; i < hashBytes.Length; i++) hashWithSaltBytes[i] = hashBytes[i]; // Append salt bytes to the result. for(int i = 0; i < SALT.Length; i++) hashWithSaltBytes[hashBytes.Length + i] = SALT[i]; // Convert result into a base64-encoded string. hashedPassword = Convert.ToBase64String(hashWithSaltBytes); return hashedPassword; }

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  • Suggest me a good php-fpm configuartion

    - by Werulz
    I am configuring a server for a friend.The server has the following specs 8GB RAM Quad Core processor 1 TB HDD 100 mbps port However all php files are loadking very slowly.I did a speedtest and server takes 16 secs to Load FIRST byte.I strongly believe its my php-fpm configuration.Server uses nginx and php only , no mysql etc... My current php-fpm configuration pm.max_children = 50 pm.start_servers = 10 pm.min_spare_servers = 5 pm.max_spare_servers = 35 Server load and ram usage are perfectly fine Please suggest me a good configuration for this server UPDATE: This configuration works fine pm.max_children = 20 pm.start_servers = 7 pm.min_spare_servers = 5 pm.max_spare_servers = 10 pm.max_requests = 100 The problem with first byte load time is solved.However after like 15-20 hours First byte load time increase gradually. I have to reload php-fpm to get small load time Based on my conf above what i modify to it so that first byte load time remain small and i don't have to restart it:P

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  • Disable antialiasing for a specific GDI device context

    - by Jacob Stanley
    I'm using a third party library to render an image to a GDI DC and I need to ensure that any text is rendered without any smoothing/antialiasing so that I can convert the image to a predefined palette with indexed colors. The third party library i'm using for rendering doesn't support this and just renders text as per the current windows settings for font rendering. They've also said that it's unlikely they'll add the ability to switch anti-aliasing off any time soon. The best work around I've found so far is to call the third party library in this way (error handling and prior settings checks ommitted for brevity): private static void SetFontSmoothing(bool enabled) { int pv = 0; SystemParametersInfo(Spi.SetFontSmoothing, enabled ? 1 : 0, ref pv, Spif.None); } // snip Graphics graphics = Graphics.FromImage(bitmap) IntPtr deviceContext = graphics.GetHdc(); SetFontSmoothing(false); thirdPartyComponent.Render(deviceContext); SetFontSmoothing(true); This obviously has a horrible effect on the operating system, other applications flicker from cleartype enabled to disabled and back every time I render the image. So the question is, does anyone know how I can alter the font rendering settings for a specific DC? Even if I could just make the changes process or thread specific instead of affecting the whole operating system, that would be a big step forward! (That would give me the option of farming this rendering out to a separate process- the results are written to disk after rendering anyway) EDIT: I'd like to add that I don't mind if the solution is more complex than just a few API calls. I'd even be happy with a solution that involved hooking system dlls if it was only about a days work. EDIT: Background Information The third-party library renders using a palette of about 70 colors. After the image (which is actually a map tile) is rendered to the DC, I convert each pixel from it's 32-bit color back to it's palette index and store the result as an 8bpp greyscale image. This is uploaded to the video card as a texture. During rendering, I re-apply the palette (also stored as a texture) with a pixel shader executing on the video card. This allows me to switch and fade between different palettes instantaneously instead of needing to regenerate all the required tiles. It takes between 10-60 seconds to generate and upload all the tiles for a typical view of the world. EDIT: Renamed GraphicsDevice to Graphics The class GraphicsDevice in the previous version of this question is actually System.Drawing.Graphics. I had renamed it (using GraphicsDevice = ...) because the code in question is in the namespace MyCompany.Graphics and the compiler wasn't able resolve it properly. EDIT: Success! I even managed to port the PatchIat function below to C# with the help of Marshal.GetFunctionPointerForDelegate. The .NET interop team really did a fantastic job! I'm now using the following syntax, where Patch is an extension method on System.Diagnostics.ProcessModule: module.Patch( "Gdi32.dll", "CreateFontIndirectA", (CreateFontIndirectA original) => font => { font->lfQuality = NONANTIALIASED_QUALITY; return original(font); }); private unsafe delegate IntPtr CreateFontIndirectA(LOGFONTA* lplf); private const int NONANTIALIASED_QUALITY = 3; [StructLayout(LayoutKind.Sequential)] private struct LOGFONTA { public int lfHeight; public int lfWidth; public int lfEscapement; public int lfOrientation; public int lfWeight; public byte lfItalic; public byte lfUnderline; public byte lfStrikeOut; public byte lfCharSet; public byte lfOutPrecision; public byte lfClipPrecision; public byte lfQuality; public byte lfPitchAndFamily; public unsafe fixed sbyte lfFaceName [32]; }

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  • Per bytes RAM memory acess

    - by b-gen-jack-o-neill
    Hi, I have just a simple question. Today memory DDR chips are 64 bits wide, and the CPU data bus is also 64 bits wide. But memory is stil organised in single bytes. So, what I want to ask is, when CPU selects some memory adress, it should be one byte, right? Becouse the lowest memory portion you can access is 1 byte. But, if you get 1 byte per 1 adress, why is memory bus 8 bytes wide?

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  • C# performance varying due to memory

    - by user1107474
    Hope this is a valid post here, its a combination of C# issues and hardware. I am benchmarking our server because we have found problems with the performance of our quant library (written in C#). I have simulated the same performance issues with some simple C# code- performing very heavy memory-usage. The code below is in a function which is spawned from a threadpool, up to a maximum of 32 threads (because our server has 4x CPUs x 8 cores each). This is all on .Net 3.5 The problem is that we are getting wildly differing performance. I run the below function 1000 times. The average time taken for the code to run could be, say, 3.5s, but the fastest will only be 1.2s and the slowest will be 7s- for the exact same function! I have graphed the memory usage against the timings and there doesnt appear to be any correlation with the GC kicking in. One thing I did notice is that when running in a single thread the timings are identical and there is no wild deviation. I have also tested CPU-bound algorithms and the timings are identical too. This has made us wonder if the memory bus just cannot cope. I was wondering could this be another .net or C# problem, or is it something related to our hardware? Would this be the same experience if I had used C++, or Java?? We are using 4x Intel x7550 with 32GB ram. Is there any way around this problem in general? Stopwatch watch = new Stopwatch(); watch.Start(); List<byte> list1 = new List<byte>(); List<byte> list2 = new List<byte>(); List<byte> list3 = new List<byte>(); int Size1 = 10000000; int Size2 = 2 * Size1; int Size3 = Size1; for (int i = 0; i < Size1; i++) { list1.Add(57); } for (int i = 0; i < Size2; i = i + 2) { list2.Add(56); } for (int i = 0; i < Size3; i++) { byte temp = list1.ElementAt(i); byte temp2 = list2.ElementAt(i); list3.Add(temp); list2[i] = temp; list1[i] = temp2; } watch.Stop(); (the code is just meant to stress out the memory) I would include the threadpool code, but we used a non-standard threadpool library. EDIT: I have reduced "size1" to 100000, which basically doesn't use much memory and I still get a lot of jitter. This suggests it's not the amount of memory being transferred, but the frequency of memory grabs?

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  • BizTalk Pipeline Component Error: "Object reference not set to an instance of an object"

    - by Stuart Brierley
    Yesterday I posted about my BizTalk Archiving Pipeline Component, which can be found on Codeplex if anyone is interested in taking a look. During testing of this component I began to encounter an error whereby the component would throw an "Object reference not set to an instance of an object" error when processing as a part of a Custom Pipeline. This was occurring when the component was reading a ReadOnlySeekableStream so that the data can be archived to file, but the actual code throwing the error was somewhere in the depths of the Microsoft.BizTalk.Streaming stack. It turns out that there is a known issue where this exception can be thrown because the garbage collector has disposed of of the stream before execution of the custom pipeline has completed. To get around this you need to add the streams in your code to the pipeline context resource tracker.   So a block of my code goes from:                         originalStrm = bodyPart.GetOriginalDataStream();                         if (!originalStrm.CanSeek)                         {                             ReadOnlySeekableStream seekableStream = new ReadOnlySeekableStream(originalStrm);                             inmsg.BodyPart.Data = seekableStream;                             originalStrm = inmsg.BodyPart.Data;                         }                         fileArchive = new FileStream(FullPath, FileMode.Create, FileAccess.Write);                         binWriter = new BinaryWriter(fileArchive);                         byte[] buffer = new byte[bufferSize];                         int sizeRead = 0;                         while ((sizeRead = originalStrm.Read(buffer, 0, bufferSize)) != 0)                         {                             binWriter.Write(buffer, 0, sizeRead);                         } to                         originalStrm = bodyPart.GetOriginalDataStream();                         if (!originalStrm.CanSeek)                         {                             ReadOnlySeekableStream seekableStream = new ReadOnlySeekableStream(originalStrm);                             inmsg.BodyPart.Data = seekableStream;                             originalStrm = inmsg.BodyPart.Data;                         }                         pc.ResourceTracker.AddResource(originalStrm);                         fileArchive = new FileStream(FullPath, FileMode.Create, FileAccess.Write);                         binWriter = new BinaryWriter(fileArchive);                         byte[] buffer = new byte[bufferSize];                         int sizeRead = 0;                         while ((sizeRead = originalStrm.Read(buffer, 0, bufferSize)) != 0)                         {                             binWriter.Write(buffer, 0, sizeRead);                         } So far this seems to have solved the issue, the error is no more, and my archive component is continuing its way through testing.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers. Originally published on blogs.oracle.com/javaone.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

    Read the article

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